Imported Debian version 2.5.3~trusty1
[deb_ffmpeg.git] / ffmpeg / libavcodec / kgv1dec.c
CommitLineData
2ba45a60
DM
1/*
2 * Kega Game Video (KGV1) decoder
3 * Copyright (c) 2010 Daniel Verkamp
4 *
5 * This file is part of FFmpeg.
6 *
7 * FFmpeg is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
11 *
12 * FFmpeg is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
16 *
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 */
21
22/**
23 * @file
24 * Kega Game Video decoder
25 */
26
27#include "libavutil/common.h"
28#include "libavutil/intreadwrite.h"
29#include "libavutil/imgutils.h"
30#include "avcodec.h"
31#include "internal.h"
32
33typedef struct {
34 uint16_t *frame_buffer;
35 uint16_t *last_frame_buffer;
36} KgvContext;
37
38static void decode_flush(AVCodecContext *avctx)
39{
40 KgvContext * const c = avctx->priv_data;
41
42 av_freep(&c->frame_buffer);
43 av_freep(&c->last_frame_buffer);
44}
45
46static int decode_frame(AVCodecContext *avctx, void *data, int *got_frame,
47 AVPacket *avpkt)
48{
49 AVFrame *frame = data;
50 const uint8_t *buf = avpkt->data;
51 const uint8_t *buf_end = buf + avpkt->size;
52 KgvContext * const c = avctx->priv_data;
53 int offsets[8];
54 uint8_t *out, *prev;
55 int outcnt = 0, maxcnt;
56 int w, h, i, res;
57
58 if (avpkt->size < 2)
59 return AVERROR_INVALIDDATA;
60
61 w = (buf[0] + 1) * 8;
62 h = (buf[1] + 1) * 8;
63 buf += 2;
64
65 if (w != avctx->width || h != avctx->height) {
66 av_freep(&c->frame_buffer);
67 av_freep(&c->last_frame_buffer);
68 if ((res = ff_set_dimensions(avctx, w, h)) < 0)
69 return res;
70 }
71
72 if (!c->frame_buffer) {
73 c->frame_buffer = av_mallocz(avctx->width * avctx->height * 2);
74 c->last_frame_buffer = av_mallocz(avctx->width * avctx->height * 2);
75 if (!c->frame_buffer || !c->last_frame_buffer) {
76 decode_flush(avctx);
77 return AVERROR(ENOMEM);
78 }
79 }
80
81 maxcnt = w * h;
82
83 if ((res = ff_get_buffer(avctx, frame, 0)) < 0)
84 return res;
85 out = (uint8_t*)c->frame_buffer;
86 prev = (uint8_t*)c->last_frame_buffer;
87
88 for (i = 0; i < 8; i++)
89 offsets[i] = -1;
90
91 while (outcnt < maxcnt && buf_end - 2 >= buf) {
92 int code = AV_RL16(buf);
93 buf += 2;
94
95 if (!(code & 0x8000)) {
96 AV_WN16A(&out[2 * outcnt], code); // rgb555 pixel coded directly
97 outcnt++;
98 } else {
99 int count;
100
101 if ((code & 0x6000) == 0x6000) {
102 // copy from previous frame
103 int oidx = (code >> 10) & 7;
104 int start;
105
106 count = (code & 0x3FF) + 3;
107
108 if (offsets[oidx] < 0) {
109 if (buf_end - 3 < buf)
110 break;
111 offsets[oidx] = AV_RL24(buf);
112 buf += 3;
113 }
114
115 start = (outcnt + offsets[oidx]) % maxcnt;
116
117 if (maxcnt - start < count || maxcnt - outcnt < count)
118 break;
119
120 if (!prev) {
121 av_log(avctx, AV_LOG_ERROR,
122 "Frame reference does not exist\n");
123 break;
124 }
125
126 memcpy(out + 2 * outcnt, prev + 2 * start, 2 * count);
127 } else {
128 // copy from earlier in this frame
129 int offset = (code & 0x1FFF) + 1;
130
131 if (!(code & 0x6000)) {
132 count = 2;
133 } else if ((code & 0x6000) == 0x2000) {
134 count = 3;
135 } else {
136 if (buf_end - 1 < buf)
137 break;
138 count = 4 + *buf++;
139 }
140
141 if (outcnt < offset || maxcnt - outcnt < count)
142 break;
143
144 av_memcpy_backptr(out + 2 * outcnt, 2 * offset, 2 * count);
145 }
146 outcnt += count;
147 }
148 }
149
150 if (outcnt - maxcnt)
151 av_log(avctx, AV_LOG_DEBUG, "frame finished with %d diff\n", outcnt - maxcnt);
152
153 av_image_copy_plane(frame->data[0], frame->linesize[0],
154 (const uint8_t*)c->frame_buffer, avctx->width * 2,
155 avctx->width * 2, avctx->height);
156 FFSWAP(uint16_t *, c->frame_buffer, c->last_frame_buffer);
157
158 *got_frame = 1;
159
160 return avpkt->size;
161}
162
163static av_cold int decode_init(AVCodecContext *avctx)
164{
165 avctx->pix_fmt = AV_PIX_FMT_RGB555;
166
167 return 0;
168}
169
170static av_cold int decode_end(AVCodecContext *avctx)
171{
172 decode_flush(avctx);
173 return 0;
174}
175
176AVCodec ff_kgv1_decoder = {
177 .name = "kgv1",
178 .long_name = NULL_IF_CONFIG_SMALL("Kega Game Video"),
179 .type = AVMEDIA_TYPE_VIDEO,
180 .id = AV_CODEC_ID_KGV1,
181 .priv_data_size = sizeof(KgvContext),
182 .init = decode_init,
183 .close = decode_end,
184 .decode = decode_frame,
185 .flush = decode_flush,
186 .capabilities = CODEC_CAP_DR1,
187};